function drop_time = drop(area_avg)
starting = 1; 
ending = length(area_avg);
answer = -1; 

while (answer==-1)
    
    
    % Move to right side if target is greater.
    if (area_avg(starting) >= -0.5)
        if starting < length(area_avg)
            starting = starting + 1;
        
        else 
            answer = length(area_avg);  
        end
        
        % Move left side.
    else
        answer = starting;
        break
    end
end
drop_time = answer; 
end